The present invention relates to a structure for mounting cameras on a vehicle, and more particularly to a mounting structure of cameras which are mounted on a vehicle for obtaining forward environmental data while running in a vehicle drive supporting system.
In recent years, a vehicle drive supporting system with a camera mounted on a vehicle has been proposed, wherein information for safety is supplied to a driver, or a vehicle control is automatically performed, based on the forward data in a vehicle running direction which are obtained by the camera while running.
Conventionally, as a mounting structure of a camera mounted on a vehicle, a structure described in a publication of Japanese Patent Application Laid-Open No. 11-78717 has been known. The publication discloses a structure for mounting a camera inside a front windshield (front glass) of a vehicle, or for mounting a camera as a unit on a room mirror for confirming a rearward direction.
When the mounting structure described in the above-mentioned publication is applied to so-called stereo cameras which have one camera on the right and left sides, respectively, two cameras are mounted on each side of a front glass through a stay. However, in this mounting method, there are problems that each position of the both cameras is apt to be relatively tilted because of unavoidable unevenness when manufacturing the front glass and a vehicle body. If each position of cameras is deviated from a correct position thereof, an accuracy of obtained image data may be lowered. As a result, for example, it may be not accurately performed to measure a distance between an own car and a forward running car, so that the vehicle drive supporting system can not be accurately operated.
Furthermore, since the cameras are independently fixed on the front glass through the stay according to the conventional method, a relative accuracy of an optical axis between the cameras mounted on the both sides is apt to change because of vibration caused while running, a distortion of vehicle body, and a temperature difference inside a vehicle, so that the accuracy of obtained image data is lowered. In addition, a posture such as angle must be adjusted in each camera upon manufacturing, wherein it takes much time to do so. As a result, a productive efficiency thereof is lowered.
The present invention has been developed in view of the aforementioned problems, and an object of the present invention is to provide a structure for mounting cameras on a vehicle wherein a relative position between cameras disposed on the both sides can be accurately kept even if vibration while running and/or a temperature difference inside a vehicle influences the cameras, so that an accuracy of the obtained image data is not lowered under any situation.
A first aspect of the present invention is to provide a structure for mounting cameras on a vehicle comprising a chassis having a predetermined length and extended in a lateral direction, a pair of cameras mounted on both sides of a vehicle for making a film of a forward road environment when running, each camera being mounted on both ends of the chassis, and a mounting seat maybe formed in a center of the chassis, wherein the mounting seat member is fixed onto a predetermined mounting position of a vehicle body so as to mount the pair of cameras on the vehicle body, and portions other than the mounting seat member of the chassis are disposed apart from the vehicle body.
According to the above-mentioned constructions, since the two cameras are mounted on the both ends of the chassis, the relative accuracy of each optical axis between the right and left cameras can be prevented from lowering due to vibration when running or temperature difference. Also, since the chassis is fixed onto the vehicle body with a small compressed area, the image data obtained from the both cameras suffers little influence of vibration when running, and the like, so that the reliability of a drive supporting system can be improved.
A second aspect of the present invention is to provide the structure for mounting cameras on a vehicle according to the first aspect which a taper plate further intervenes between the mounting seat member and the mounting position on the vehicle body when fixing the chassis onto the mounting position of the vehicle body.
A third aspect of the present invention is to provide the structure for mounting cameras on a vehicle according to the first aspect which a plurality of taper plates are further prepared in advance, the taper plates being formed by wedgelike plates with different taper angle when fixing the chassis onto the mounting position of the vehicle body, wherein the taper plate having the most adequate taper angle of the plurality of taper plates intervenes between the mounting seat member and the vehicle body so as to dispose the pair of cameras mounted on the chassis in the predetermined mounting position of the vehicle body.
According to the above-mentioned second and third constructions, since the taper plate intervenes between the mounting seat member and a front rail of the vehicle body, it becomes easy to adjust the direction of the optical axis of the right and left cameras, so that a manufacturing efficiency can be improved.
A fourth aspect of the present invention is to provide the structure for mounting cameras on a vehicle according to the first to third aspects further comprising falling prevention members for engaging the both ends of the chassis with the vehicle body.
According to the above-mentioned fourth construction, since the falling prevention member is provided on the both ends of the chassis, it becomes easy to mount the chassis onto the vehicle body.